need help!

How do you wire up a trimmer capacitor to a circuit. I'm trying to build a simple transmitter. The capacitor is a Xicon Ceramic Trimmer Capacitor 6.0-70 PFD


if anyone can help thanks,
Jacob

tj107us said:

How do you wire up a trimmer capacitor to a circuit. I'm trying to build a simple transmitter. The capacitor is a Xicon Ceramic Trimmer Capacitor 6.0-70 PFD

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As part of the tuned circuit that governs the frequency - assuming you want it to vary the frequency?, but your question is so vague as to make it impossible to give any specific answer.

it has three poles, and i have only two wires. does that help you a little bit?

tj107us said:

it has three poles, and i have only two wires. does that help you a little bit?

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Two will be connected together, either check with a meter, or just with your eyes (it's usually pretty obvious).

If your trimmer cap is part of a VCO, or in any other circuit where the cap values are small, be very careful how you "wire" it up. Direct connection to the circuit is prefferable as even fairly short leads can introduce significant capacitance into that kind of circuit.

im sorry i really dont understand.

Is the inside of the variable capacitor just like the inside of a resistive voltage divider, except that it has two capacitors intead of two resistors? That would explain the 3 leads and if you wanted to use it as a variable capacitor instead of a capacitive voltage divider, then you would short the center lead and one end lead together to bypass the second capacitor. Refer to the attached image.

The center lead wipes up and down to decrease the value of one resistor/capacitor while increasing the value of the other to change the ratios. In actuality the variable resistors/capacitors are meant to be used as adjustable "dividers", but you turn them into regular variable capacitors/resistors by shorting the center lead with an end lead to remove the second capacitor/resistor.

**broken link removed**

1-----|(------|(----2
`````````^
`````````|
`````````3

1 and 2 are the end leads, 3 is the lead that moves around to change the ratio of the divider. To make it a regular variable capacitor, connect either 1/3 or 2/3. This will bypass the second capacitor and basically remove it from the circuit by producing a short-circuit across it.

MR MODERATOR:
Is it possible to enable it so that blank spaces can be accepted so we don't have to use periods as space fillers?

dknguyen said:

MR MODERATOR:
Is it possible to enable it so that blank spaces can be accepted so we don't have to use periods as space fillers?

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No, as it's your browser that removes the spaces, it's part of the HTML specification.

However, YOU can avoid this by using the 'code' tags.

Could you also try thinking before you post?, or at least editing posts after you've made them? - I'm getting rather tired of deleting your empty posts!, three in this thread so far!. No one else does this repeatedly like you!.

dknguyen said:

Is the inside of the variable capacitor just like the inside of a resistive voltage divider, except that it has two capacitors intead of two resistors? That would explain the 3 leads

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No! The variable capacitor is a single capacitor whose value is adjusted mechanically. It has two connections but one is duplicated so it mounts securely with 3 pins on a pcb.

Don't make drawings using ASCII text. Use a drawing program like MS Paint instead.